The worm gear mechanism

Worm gear mechanism (44) includes a worm (70), and meshing with a worm wheel (80) to the worm consists. The hob used for gear cutting of the worm wheel teeth (90), at least addendum surface (91c) is formed in a circular arc shape. The radius of the arc of the center of the tooth end faces (93) are located on the hob of the center line (WL ') nearer the hob pitch line (94). The worm wheel is gear cutting by the hob. The worm is formed on the hob and the same shape. Keep away from him meshing length of the worm gear mechanism (L), rather than to keep away from him meshing length of the conventional worm gear mechanism (Llim), set to be larger.